Quick facts

Common name: brook lamprey

Scientific name: Lampetra planeri

Family: Lamprey

Habitat: woodland brooks, streams, rivers, occasionally lakes

Diet: detritus, however they do not feed as adults

Predators: herons, otters and large predatory fish

Origin: native

What do brook lampreys look like?

Brook lampreys have a long, eel-like body and measure between 15-25cm as an adult. They are greenish-grey in colour and have two back fins, along with gill openings on either side of the head. They do not have a jaw; instead they have a round sucker for a mouth. They have one single nostril on top of their head and their larvae begin life with no eyes or mouth.

Brook lamprey sucking on stone

Credit: Blickwinkel / Alamy Stock Photo

What do brook lampreys eat?

The brook lamprey only feeds when in its larval form, filtering detritus and other organic matter from the water. Once it transforms into an adult, its digestive functions stop and it becomes unable to feed altogether.

Did you know?

Unlike other lamprey species, brook lampreys do not migrate out to sea in order to breed. Instead, they spend their entire lifecycle in rivers and streams.

How do brook lampreys breed?

Adults spawn in the shallow parts of streams from April to June. Both male and females work to build nests, using their sucker-like mouths to pick up rocks and create pits in the stream bed. Several males mate with a female, and eggs are then deposited into the nests.

Eggs hatch within a few days and the young lamprey stay in the larvae stage for around three to seven years. They live buried in the sand and metamorphose into adults during the autumn. This is when they develop eyes and a mouth but stop feeding entirely. A few weeks after spawning the adults die.

Brook lamprey full body

Credit: Blickwinkel / Alamy Stock Photo

Where do brook lampreys live?

Brook lampreys are a freshwater species, living in streams, rivers and occasionally lakes.

Did you know?

During spawning, the anal and mouth areas of the brook lamprey turn an orangey red.

Signs and spotting tips

As they spend much of their time hiding in sandy sediments, it can be difficult to spot brook lamprey. The best time to see them is during the spawning season, which takes place in the spring. Head to the shallower areas of brooks, streams and rivers and you might just see the spawning clusters in action.

Brook lamprey larva

Credit: Blickwinkel / Alamy Stock Photo

Threats and conservation

The biggest threats to the brook lamprey are habitat loss/degradation and pollution.

Did you know?

The brook lamprey’s skeleton is made up of cartilage, not bone.